maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/ThinLTO/X86/weak_globals_import.ll

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

34 lines
1.1 KiB
LLVM
Raw Normal View History

[ThinLTO] Fix import of multiply defined global variables Currently, if there is a module that contains a strong definition of a global variable and a module that has both a weak definition for the same global and a reference to it, it may result in an undefined symbol error while linking with ThinLTO. It happens because: * the strong definition become internal because it is read-only and can be imported; * the weak definition gets replaced by a declaration because it's non-prevailing; * the strong definition failed to be imported because the destination module already contains another definition of the global yet this def is non-prevailing. The patch adds a check to computeImportForReferencedGlobals() that allows considering a global variable for being imported even if the module contains a definition of it in the case this def has an interposable linkage type. Note that currently the check is based only on the linkage type (and this seems to be enough at the moment), but it might be worth to account the information whether the def is prevailing or not. Reviewed By: tejohnson Differential Revision: https://reviews.llvm.org/D95943
2021-02-02 18:13:43 +08:00
; RUN: split-file %s %t.dir
; RUN: opt -module-summary %t.dir/1.ll -o %t1.bc
; RUN: opt -module-summary %t.dir/2.ll -o %t2.bc
; RUN: llvm-lto2 run -save-temps %t1.bc %t2.bc -o %t.out \
; RUN: -r=%t1.bc,main,plx \
; RUN: -r=%t1.bc,G \
; RUN: -r=%t2.bc,G,pl
; RUN: llvm-dis %t.out.1.3.import.bc -o - | FileCheck %s
; RUN: llvm-dis %t.out.2.3.import.bc -o - | FileCheck %s
; Test that a non-prevailing def with interposable linkage doesn't prevent
; importing a suitable definition from a prevailing module.
; CHECK: @G = internal local_unnamed_addr global i32 42
;--- 1.ll
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@G = weak dso_local local_unnamed_addr global i32 0, align 4
define dso_local i32 @main() local_unnamed_addr {
[IR] Enable opaque pointers by default This enabled opaque pointers by default in LLVM. The effect of this is twofold: * If IR that contains *neither* explicit ptr nor %T* types is passed to tools, we will now use opaque pointer mode, unless -opaque-pointers=0 has been explicitly passed. * Users of LLVM as a library will now default to opaque pointers. It is possible to opt-out by calling setOpaquePointers(false) on LLVMContext. A cmake option to toggle this default will not be provided. Frontends or other tools that want to (temporarily) keep using typed pointers should disable opaque pointers via LLVMContext. Differential Revision: https://reviews.llvm.org/D126689
2022-05-31 17:58:35 +08:00
%1 = load i32, ptr @G, align 4
[ThinLTO] Fix import of multiply defined global variables Currently, if there is a module that contains a strong definition of a global variable and a module that has both a weak definition for the same global and a reference to it, it may result in an undefined symbol error while linking with ThinLTO. It happens because: * the strong definition become internal because it is read-only and can be imported; * the weak definition gets replaced by a declaration because it's non-prevailing; * the strong definition failed to be imported because the destination module already contains another definition of the global yet this def is non-prevailing. The patch adds a check to computeImportForReferencedGlobals() that allows considering a global variable for being imported even if the module contains a definition of it in the case this def has an interposable linkage type. Note that currently the check is based only on the linkage type (and this seems to be enough at the moment), but it might be worth to account the information whether the def is prevailing or not. Reviewed By: tejohnson Differential Revision: https://reviews.llvm.org/D95943
2021-02-02 18:13:43 +08:00
ret i32 %1
}
;--- 2.ll
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@G = dso_local local_unnamed_addr global i32 42, align 4